Free and defect-bound (bi)polarons in LiNbO_{3}: Atomic structure and spectroscopic signatures from ab initio calculations
Polarons in dielectric crystals play a crucial role for applications in integrated electronics and optoelectronics. In this work, we use density-functional theory and Green's function methods to explore the microscopic structure and spectroscopic signatures of electron polarons in lithium nioba...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2020-10-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.2.043002 |
| _version_ | 1797211302782828544 |
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| author | Falko Schmidt Agnieszka L. Kozub Timur Biktagirov Christof Eigner Christine Silberhorn Arno Schindlmayr Wolf Gero Schmidt Uwe Gerstmann |
| author_facet | Falko Schmidt Agnieszka L. Kozub Timur Biktagirov Christof Eigner Christine Silberhorn Arno Schindlmayr Wolf Gero Schmidt Uwe Gerstmann |
| author_sort | Falko Schmidt |
| collection | DOAJ |
| description | Polarons in dielectric crystals play a crucial role for applications in integrated electronics and optoelectronics. In this work, we use density-functional theory and Green's function methods to explore the microscopic structure and spectroscopic signatures of electron polarons in lithium niobate (LiNbO_{3}). Total-energy calculations and the comparison of calculated electron paramagnetic resonance data with available measurements reveal the formation of bound polarons at Nb_{Li} antisite defects with a quasi-Jahn-Teller distorted, tilted configuration. The defect-formation energies further indicate that (bi)polarons may form not only at Nb_{Li} antisites but also at structures where the antisite Nb atom moves into a neighboring empty oxygen octahedron. Based on these structure models, and on the calculated charge-transition levels and potential-energy barriers, we propose two mechanisms for the optical and thermal splitting of bipolarons, which provide a natural explanation for the reported two-path recombination of bipolarons. Optical-response calculations based on the Bethe-Salpeter equation, in combination with available experimental data and new measurements of the optical absorption spectrum, further corroborate the geometries proposed here for free and defect-bound (bi)polarons. |
| first_indexed | 2024-04-24T10:24:20Z |
| format | Article |
| id | doaj.art-e8817c1fe3344c54a0bb8795bc215469 |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:24:20Z |
| publishDate | 2020-10-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-e8817c1fe3344c54a0bb8795bc2154692024-04-12T17:01:40ZengAmerican Physical SocietyPhysical Review Research2643-15642020-10-012404300210.1103/PhysRevResearch.2.043002Free and defect-bound (bi)polarons in LiNbO_{3}: Atomic structure and spectroscopic signatures from ab initio calculationsFalko SchmidtAgnieszka L. KozubTimur BiktagirovChristof EignerChristine SilberhornArno SchindlmayrWolf Gero SchmidtUwe GerstmannPolarons in dielectric crystals play a crucial role for applications in integrated electronics and optoelectronics. In this work, we use density-functional theory and Green's function methods to explore the microscopic structure and spectroscopic signatures of electron polarons in lithium niobate (LiNbO_{3}). Total-energy calculations and the comparison of calculated electron paramagnetic resonance data with available measurements reveal the formation of bound polarons at Nb_{Li} antisite defects with a quasi-Jahn-Teller distorted, tilted configuration. The defect-formation energies further indicate that (bi)polarons may form not only at Nb_{Li} antisites but also at structures where the antisite Nb atom moves into a neighboring empty oxygen octahedron. Based on these structure models, and on the calculated charge-transition levels and potential-energy barriers, we propose two mechanisms for the optical and thermal splitting of bipolarons, which provide a natural explanation for the reported two-path recombination of bipolarons. Optical-response calculations based on the Bethe-Salpeter equation, in combination with available experimental data and new measurements of the optical absorption spectrum, further corroborate the geometries proposed here for free and defect-bound (bi)polarons.http://doi.org/10.1103/PhysRevResearch.2.043002 |
| spellingShingle | Falko Schmidt Agnieszka L. Kozub Timur Biktagirov Christof Eigner Christine Silberhorn Arno Schindlmayr Wolf Gero Schmidt Uwe Gerstmann Free and defect-bound (bi)polarons in LiNbO_{3}: Atomic structure and spectroscopic signatures from ab initio calculations Physical Review Research |
| title | Free and defect-bound (bi)polarons in LiNbO_{3}: Atomic structure and spectroscopic signatures from ab initio calculations |
| title_full | Free and defect-bound (bi)polarons in LiNbO_{3}: Atomic structure and spectroscopic signatures from ab initio calculations |
| title_fullStr | Free and defect-bound (bi)polarons in LiNbO_{3}: Atomic structure and spectroscopic signatures from ab initio calculations |
| title_full_unstemmed | Free and defect-bound (bi)polarons in LiNbO_{3}: Atomic structure and spectroscopic signatures from ab initio calculations |
| title_short | Free and defect-bound (bi)polarons in LiNbO_{3}: Atomic structure and spectroscopic signatures from ab initio calculations |
| title_sort | free and defect bound bi polarons in linbo 3 atomic structure and spectroscopic signatures from ab initio calculations |
| url | http://doi.org/10.1103/PhysRevResearch.2.043002 |
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